It has long been a problem of harvesting equipment to determine the amount of grain which has been stored within the bin of the combine. Initially, it was necessary for the operator to turn around and physically took into the grain bin to determine the level of grain. As the cost of crop production rises, any spillage of grain becomes more and more expensive for the farmer, and it becomes more critical to ensure that the grain bin does not overflow onto the ground. Additionally, many harvesters now utilize grain bin extensions, making the bin taller than the top of the cab, and thereby preventing viewing of the grain level from within the cab.
Various monitoring systems are now available for harvesters which are much more effective than requiring the operator to physically view the contents of the combine grain bin. A majority of the most common monitoring systems utilize a mechanical switch or float within the grain bin that triggers a light or warning device for the operator. However, these devices measure the level at a point in the bin, and are ineffective in determining the crop level when the crop flows around the mechanical sensor rendering it immobile, or when gravity forces the crop away from the sensor.
There is a need for an improved monitoring system for harvester grain bins.